Method and system for selecting and recording biopsy sites in a body organ

ABSTRACT

A method and system for selecting and recording biopsy sites in a body organ. The method comprises obtaining a three-dimensional image of the organ; and a first two-dimensional sub-image of the organ. The position of the first two-dimensional sub-image in the three-dimensional image is determined. Sites in the first two-dimensional sub-image where a biopsy is to be obtained are selected, and sites at which biopsies were obtained are indicated in the three-dimensional image. Additional two-dimensional sub-images of the organ are sequentially obtained, and for each sub-image, the position of the sub-image in the three-dimensional image is determined, and any sites in the sub-image where biopsies have previously been obtained are indicated. One or more sites in the sub-image where biopsies are to be obtained are selected and any sites where biopsies were obtained are indicated in the three-dimensional image.

FIELD OF THE INVENTION

[0001] The present invention relates to methods and systems for imaging a body tissue or organ.

BACKGROUND OF THE INVENTION

[0002] In the diagnosis of a clinical condition in a body tissue or organ, it is known to obtain a number of biopsies from the tissue or organ. For example, in the diagnosis of prostate or breast cancer, a region of the organ is imaged using ultrasonic radiation. The practitioner obtains a 2D image of the region of the organ and then, based on the image, selects a site in the organ from where a biopsy is to be obtained. A cannula is then introduced into the organ to the site and a biopsy is obtained. The cannula is typically integrated with the ultrasound transducer, and the cannula as well as the site in the image from which the cannula is poised to obtain a biopsy is indicated in the image. After obtaining the biopsy, another 2D image of another region of the organ or tissue may be obtained (by moving the ultrasound transducer) and an additional site of the organ or tissue may be selected for obtaining a biopsy. This process may be repeated several times so as to yield a number of biopsies from different sites of the organ or tissue.

[0003] In this method of obtaining biopsies, it is difficult for the practitioner to visualize in three dimensions the spatial relationship among the biopsy sites. This is due to the fact that each time the practitioner moves the ultrasound transducer to obtain a new image, the practitioner must remember bow the transducer was moved in order to visualize in his mind the spatial relationship between the presently and previously imaged regions and the perspectives from which the regions were imaged. The inability to accurately determinate and record the spatial relationships among the imaged regions often results in biopsies not being obtained from sites where a biopsy should have been obtained.

SUMMARY OF THE INVENTION

[0004] The present invention provides a system and method for selecting and recording biopsy sites within a body organ. In accordance with the invention, a three-dimensional image of at least a portion of the organ is obtained using a three-dimensional imaging device such as a three-dimensional ultrasound imaging transducer. The three dimensional image may be analyzed for regions that are suspected of having a predetermined condition such as a malignancy. For example, applicant's co-pending U.S. patent application Ser. No. 09/874,919 filed on Jun. 5, 2001 discloses a method for detecting malignancies in a tissue. The image is processed to produce a grid-like three-dimensional representation of the three-dimensional contour of the organ. This grid representation of the image is displayed on a display screen. The grid representation of the contour allows the interior of the organ to be visualized through the surface. Regions in the image suspected of having a predetermined condition such as malignancy may be indicated in the grid representation. A sub-region of the organ is then imaged. The sub-region may be imaged using either a two-dimensional imaging system such as an ultrasound system having a two-dimensional transducer, or a three-dimensional imaging system. The image of the sub-region, referred to herein as a “sub-image” is displayed on a display screen. The sub-image is analyzed and its position within the grid representation of the organ is determined. This may be done by using one or more reference points that are present in the image of the organ and the sub-image (e.g. a bone feature or artificially inserted clips present in the image and sub-image). Alternatively, this may be done in a calculation based upon the orientation of the transducers relative to the body organ when the image and sub-image were obtained. The sub-image is then indicated in the displayed grid representation of the organ. The sub-image and the grid representation showing the sub-image are thus displayed simultaneously. Regions in the sub-image suspected of having the predetermined condition are preferably indicated in the displayed sub-image.

[0005] The practitioner decides at which sites, if any, in the sub-image, a biopsy is to be obtained. The locations of any biopsies obtained are indicated in the sub-image as well as in the grid-representation.

[0006] Additional sub-images of the organ may then be obtained and displayed. For each sub-image, the position of the sub-image is indicated in, the grid representation. Sites in the sub-image where biopsies were previously obtained are indicated in the sub-image. Sites in the sub-image suspected of having the predetermined condition are preferably indicated in the sub-image. The practitioner then decides at which sites, if any, in this sub-image, a biopsy is to be obtained. The locations of any biopsies obtained are indicated in the sub-image as well as in the grid-representation.

[0007] Since the location of a current-sub-image is indicated in the grid representation together with the locations of any previous sub-regions, the practitioner can select sub-images in an orderly fashion. If sites suspected of having a predetermined condition are indicated in the grid representation and in the sub-images, the practitioner can obtain biopsies from all suspected sites.

[0008] In a preferred embodiment, the transducer used to obtain sub-images has an integrated cannula that is used to obtain a biopsy at a site in a sub-image. The sub-image includes a sign indicative of the site in the sub-image from which the cannula is poised to remove tissue for a biopsy. This allows the practitioner to select a site from which a biopsy is to be obtained based upon the spatial relationship of the site to sites in the image where biopsies were previously obtained. In particular, if suspected sites are indicated in the sub-image, the practitioner can position the cannula to obtain biopsies from the suspected sites.

[0009] The invention thus provides, in one of its aspects, a method for selecting and recording biopsy sites in a body organ comprising:

[0010] a) obtaining a three-dimensional image of a three dimensional region of the organ;

[0011] b) obtaining a first two-dimensional sub-image of a first two-dimensional sub-region of the three-dimensional region;

[0012] c) determining the position of the first two-dimensional, sub-image in the three-dimensional image;

[0013] d) optionally selecting one or more sites in the first two-dimensional sub-image where a biopsy is to be obtained;

[0014] e) indicating in the three-dimensional image any sites at which biopsies were obtained;

[0015] f) obtaining an additional two-dimensional sub-image of an additional two-dimensional sub-region of the organ, the additional two-dimensional sub-region, being included in the three-dimensional region;

[0016] g) determining the position of the additional two-dimensional sub-image in the three-dimensional image;

[0017] h) indicating in the additional two-dimensional sub-image any sites where biopsies have previously been obtained;

[0018] i) optionally selecting one or more sites in the additional two-dimensional sub-image where biopsies are to be obtained;

[0019] j) indicating in the three-dimensional image any sites where biopsies were previously obtained; and

[0020] k) repeating steps f) to j) as required.

[0021] In another of its aspects, the invention provides a system for selecting and recording biopsy sites in a body organ comprising:

[0022] (a) A three-dimensional imaging device providing a three-dimensional image of a three dimensional region of the organ;

[0023] (b) A two-dimensional imaging device providing two-dimensional sub-images of two-dimensional sub-regions of the three-dimensional region;

[0024] (c) One or more display screens for displaying a representation of the three dimensional image and for displaying one or more two-dimensional images;

[0025] (d) Means for selecting one or more sites in a two-dimensional sub-image where a biopsy is to be obtained;

[0026] (e) A processor configured to:

[0027] (i) determine the position of a two-dimensional sub-image in the three-dimensional image;

[0028] (ii) display on a display screen a representation of a three-dimensional image with an indication of the position of a two-dimensional sub-image in the three-dimensional image;

[0029] (iii) display on a display screen one or more two-dimensional sub-images;

[0030] (iv) determine in a three-dimensional image any sites at which biopsies were obtained and indicate in a displayed representation of the three-dimensional image any sites at which biopsies were obtained;

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0031] First Embodiment

[0032]FIG. 1 shows a system, generally indicated by 100, for selecting and recording biopsy sites in an organ in accordance with one embodiment of the invention. The system 100 comprises a three-dimensional imaging device 105 that is used to obtain a three-dimensional image of at least a portion of a body organ. The 3D imaging device 105 shown in FIG. 1 is a 3D ultrasound imaging device. This is by way of example only, and any 3D imaging device may be used in accordance with the invention. The imaging device 105 includes a transducer 110 that is positioned in the vicinity of the organ to be imaged to obtain a 3D image of the organ. The transducer 110 shown in FIG. 1 is adapted to be inserted into a rectum in order to image a prostate gland. This is also by way of example only. An image captured by the transducer 110 is input to a processor 115 associated with the imaging device 105. The processor 115 is configured to store a captured image in a memory 120. The processor 115 is further configured to display a planar section of a captured image on a display screen 125.

[0033] A processor 130 is configured to analyze and process a captured 3D image. The processor 130 may be the same processor as the processor 115, or may be a separate processor, as shown in FIG. 1. In the latter case, data indicative of an image may be transmitted from the processor 115 to the processor 130 over a data transmission line 135. Alternatively, the data may be recorded on a data storage medium, such as a floppy disk, and manually inserted into a disk drive 140 associated with the processor 130. The processor 130 is configured to process a captured 3D image and to generate a 3D grid representation of the surface of the organ. FIG. 2 shows a grid representation 200 of the surface of an organ. In the grid representation 200, a discrete set of curves 205 are visualized on the surface of the organ, allowing the interior of the organ to be viewed.

[0034] Referring again to FIG. 1, The processor 130 is configured to display the grid representation on a display screen 140 which may be the display screen 125, or may be a different display screen. The processor 130 is preferably further configured to analyze a captured 3D image, and to detect regions in the imaged organ suspected of having a predetermined condition, such as a malignancy. Suspected regions may be indicated in the displayed grid representation 200, by coloring the corresponding regions in the grid representation with a color that is different from the color of the curves 225. For example, the 3D region 230 in the grid representation 200 may be a region suspected of having the predetermined condition. The region 230 appears behind portions of the curves 225 in the foreground (represented by solid lines) and in front of portions of the curves 225 in the background (represented by broken lines).

[0035]FIG. 3 shows the transducer 110 in greater detail. The transducer 110 has a handle 300, and a shaft 305. The tip 310 of the shaft houses an array 315 of ultrasound transceivers that emit ultrasound waves and detect waves reflected from the body of a subject. The shaft 305 is dimensioned to be inserted though the subjects anus into the rectum. The transducer 305 also includes a cannula 320 that is used for obtaining biopsies. The cannula 305 has a trocar 325 at its tip for collecting biopsy material. The cannula 320 is slidable parallel to the shaft 305 by means of a handle 330, between a first position in which it does not extend beyond the tip, as shown in FIG. 3, and a second position in which it extends beyond the tip 315 (not shown), for collecting biopsy material. The shaft 305 is inserted into the body with the cannula 320 not extending beyond the tip of the shaft. When biopsy material is to be collected, as described below, the cannula 320 is translated along the shaft 305 so that the cannula 320 extends beyond the tip, until the trocar 325 has arrived at the site where biopsy material is to be collected.

[0036] The shaft 305 contains a set of calibration marks 335 along its length that allow determination of the depth of insertion of the shaft 305 into the body. The transducer also includes a linear and angular acceleration detector 340 that surrounds the shaft 305. The linear and angular acceleration detector 340 allows determination of the change in the translational and angular position of the transceiver array 315 in space when the transceiver array 315 is moved from a first position to a second position. Changes in the spatial orientation of the shaft 305 as determined from the detector 340 is input to the processor 130. The processor 130 is configured to determine from the inputted readings the current location and spatial orientation of the transceiver array 315 in the body relative to a previous location and spatial orientation of the transceiver array 315.

[0037] After a 3D image of the organ has been obtained and a grid representation of the organ generated and displayed, as described above, a 2D sub-image of a planar sub-region of the organ is obtained using the imaging device 105. The 2D sub-region is displayed on the display screen 140 next to the grid representation 200 of the organ. The location and spatial orientation of the transceiver array 315 when the sub-image is obtained may or may not be the same as that when the 3D image was obtained. However, any change in the spatial orientation of the transceiver array 315 that occurred when the transceiver array 315 was moved from its position when the 3D image was obtained to its position when the 2D sub-image was obtained is known from the angular acceleration detector 340. Therefore, the location of the sub-image within the 3D image can be determined. The processor 130 is configured to indicate this sub-region in the grid representation 200, preferably using a different color from the color used to indicate the grid lines 225 and suspected regions, such as the suspected region 230. FIG. 2 shows representation of an imaged planar sub-region 235 in the grid representation 200. The planar sub-region 235 intersects the suspected region 230. The intersection of the planar sub-region 235 with suspected regions, such as the suspected region 230, is indicated in the image of the sub-region 235 on the display screen.

[0038] The processor 130 is further configured to indicate in the displayed image of the sub-region the site where the cannula 320 is poised to obtain biopsy material. For example, the dot 240 in FIG. 2 shows that the cannula is poised to obtain a biopsy from the vicinity of the dot 240 in the sub-region 235. The practitioner thus manipulates the transducer 110 so as to position the transceiver array 315 into a location and spatial orientation producing a sub-image in which the cannula 320 is poised to obtain biopsy material from a site which the practitioner has selected. Biopsy material is then obtained from the selected site. The site in the organ from which biopsy material was obtained is indicated in the grid representation 200.

[0039] Additional 2D sub-images of the organ may then be obtained, as processed as above. For each sub-image, the position of the sub-image in the 3D image is indicated in the grid-representation of the organ. Locations in the sub-image suspected of having the predetermined condition, as well as sites in the sub-image where biopsies were previously performed, are indicated in the displayed image. The site in the sub-image at which the cannula 320 is poised to obtain biopsy material is also indicated in the image. If the practitioner decides to obtain biopsy material from this site, a biopsy is obtained.

[0040] Indicating in the grid-representation the site in the organ of each biopsy as the biopsy is obtained insures that biopsies are obtained from all selected sites, and moreover allows the site of each biopsy in the organ to be recorded for future reference. Displaying simultaneously on a displayed sub-image regions suspected of having a predetermined condition, such as malignancy as well as the site where the cannula 320 is poised to obtain biopsy material, allows biopsies to be made in the suspected regions.

[0041] Second Embodiment

[0042]FIG. 4 shows a system, generally indicated by 400, for selecting and recording biopsy sites in an organ, in accordance with another embodiment of the invention. The system 400 has components in common with the system 100, and similar components in the two systems are identified by the same reference numeral, without further explanation. In contrast to the system 100 in which the imaging device 105 is used to obtain a 3D image of a body organ as well as 2D sub-images, the system, 400 comprises a three-dimensional imaging device 105 that is used to obtain only three-dimensional images of at least a portion of a body organ. A separate imaging device 405 is used to obtain two-dimensional sub-images of the organ. The imaging device 405 will be referred to herein as a “2D imaging device”, although it may in fact be capable of 3D imaging. The 2D imaging device 405 shown in FIG. 4 is a 2D ultrasound imaging device. This is by way of example only, and any 2D imaging device may be used in accordance with the invention. The imaging device 405 includes a transducer 410 that is positionable in the vicinity of the organ to be imaged to obtain a 2D sub-image of the organ. The transducer 410 shown in FIG. 4 is adapted to be inserted into a rectum in order to image a prostate gland. This is also by way of example only. A sub-image captured by the transducer 410 is input to a processor 415 associated with the imaging device 405. The processor 415 is configured to store a captured sub-image in a memory 420. The processor 415 is further configured to display a sub-image on a display screen 425.

[0043] The processor 130 is configured to analyze and process a captured 2D sub-image. The processor 130 may be the same processor as the processor 115 or the processor 415, or may be a separate processor, as shown in FIG. 4. In the latter case, data indicative of an image may be transmitted from the processor 415 to the processor 130 over a data transmission line 435. Alternatively, the data indicative of a sub-image may be recorded on a data storage medium, such as a floppy disk, and manually inserted into the disk drive 140 associated with the processor 130.

[0044] Since separate imaging devices are used to obtain the 3D image and 2D sub-images, the 3D image obtained by the imaging device 105 must contain one or more identifiable reference points that may be for example, a bone feature or clips artificially introduced into the organ. The processor 130 is configured to process a captured 3D image obtained by the 3D imaging system 105 and to generate a 3D grid representation of the surface of the organ, as was explained in The first embodiment in reference to FIG. 2. The processor 130 is configured to display the grid representation on a display screen 140 which may be the display screen 125, the display screen 425, or may be a different display screen, as shown in FIG. 4. The processor 130 is preferably further configured to analyze a captured 3D image, and to detect regions in the imaged organ suspected of having a predetermined condition, such as a malignancy. Suspected regions may be indicated in the displayed grid representation 200, by coloring the corresponding regions in the grid representation with a color that is different from the color of the curves 225, as described in The first embodiment.

[0045]FIG. 5 shows the transducer 410 in greater detail. The transducer 410 is in principle similar in shape and structure to the transducer 110, since both transducers are used to image the same organ. The transducer has several components in common with the transducer 110, and similar components are indicated by the same reference numeral without further explanation. In particular, the shaft 305 of the transducer 410 contains a set of calibration marks 335 along its length and a linear and angular acceleration detector 340 that surrounds the shaft 305. The tip 310 of the shaft 305 houses an array 515 of ultrasound transceivers that emit ultrasound waves and detect waves reflected from the body of a subject. The depth of penetration of the shaft 305 in the body as determined from the calibration marks 335 or from inserted clips.

[0046] The transducer 410 also includes a cannula 320 that is used for obtaining biopsies, as described in Example 1. Unlike the transducer 110 of the system 100, the transducer 110 of the system 400 need not have a cannula, as only the transducer 410, and not the transducer 110, is used for obtaining biopsies with the system 400.

[0047] After a 3D image of the organ has been obtained by the 3D imaging device 105, and a grid representation of the organ generated and displayed, as described above, a 2D sub-image of a planar sub-region of the organ is obtained using the imaging device 405. The 2D sub-image must contain the reference points present in the 3D image in order to determine the difference between the position and spatial orientation of the transceiver array 315 when the 3D image was obtained, and the transceiver array 515 when the 2D sub-image was obtained. The position of the transceiver array 515 when the 2D sub-image was obtained is preferably the same as that of the transceiver array 315 when the 3D image was obtained. The location of the sub-image obtained by the 2D imaging device 405 in the 3D image obtained by the 3D imaging device 105 can therefore be determined. The 2D sub-region is displayed on the display screen 140 next to the grid representation 200 of the organ. The processor 130 is configured to indicate this sub-region in the grid representation 200, as described in the first embodiment in reference to FIG. 2.

[0048] The processor 130 is further configured to indicate in the displayed image of the sub-region the site where the cannula 320 on the transducer 410 is poised to obtain biopsy material, as explained in The first embodiment. The practitioner thus manipulates the transducer 410 so as to position the transceiver array 515 into a location and spatial orientation producing a sub-image in which the cannula 320 of the transducer 410 is poised to obtain biopsy material from a site which the practitioner has selected. Biopsy material is then obtained from the selected site. The site in the organ from which biopsy material was obtained is indicated in the grid representation 200.

[0049] As in the first embodiment, additional 2D sub-images of the organ may then be obtained, as described above. For each additional 2D sub-image, the change in the location and angular orientation of the transducer 410 that occurred when it was moved after the previous 2D sub-image was obtained, is determined from the linear and angular acceleration detector 340 on the transducer 410. For each sub-image, the position of the sub-image in the 3D image is indicated in the grid-representation of the organ. Locations in the sub-image suspected of having the predetermined condition as well as sites in the sub-image where biopsies were previously performed, are indicated in the displayed image. The site in the sub-image at which the cannula 320 of the transducer 410 is poised to obtain biopsy material is also indicated in the image. If the practitioner decides to obtain biopsy material from this site, a biopsy is obtained.

[0050] Indicating in the grid-representation the site in the organ of each biopsy as the biopsy is obtained insures that biopsies are obtained from all selected sites, and moreover allows the site of each biopsy in the organ to be recorded for future reference. Displaying simultaneously on a displayed sub-image regions suspected of having a predetermined condition, such as malignancy as well as the site where the cannula 320 of the transducer 410 is poised to obtain biopsy material, allows biopsies to be made in the suspected regions. 

1. A method for selecting and recording biopsy sites in a body organ comprising: a) obtaining a three-dimensional image of a three dimensional region of the organ; b) obtaining a first two-dimensional sub-image of a first two-dimensional sub-region of the three-dimensional region; c) determining the position of the first two-dimensional sub-image in the three-dimensional image; d) optionally selecting one or more sites in the first two-dimensional sub-image where a biopsy is to be obtained; e) indicating in the three-dimensional image any sites at which biopsies were obtained; f) obtaining an additional two-dimensional sub-image of an additional two-dimensional sub-region of the organ, the additional two-dimensional sub-region being included in the three-dimensional region; g) determining the position of the additional two-dimensional sub-image in the three-dimensional image; h) indicating in the additional two-dimensional sub-image any sites where biopsies have previously been obtained; i) optionally selecting one or more sites in the additional two-dimensional sub-image where biopsies are to be obtained; j) indicating in the three-dimensional image any sites where biopsies were previously obtained; and k) repeating steps f) to j) as required.
 2. The method according to claim 2 wherein the organ is a prostate or breast.
 3. The method according to any one of the previous claims wherein the three-dimensional image is obtained by three-dimensional ultrasound.
 4. The method according to any one of the previous claims wherein one or more two-dimensional sub-images are obtained by two-dimensional ultasound.
 5. The method according to any one of the previous claims wherein the three-dimensional image is displayed as a grid representation.
 6. The method according to any one of the previous claims further comprising obtaining a biopsy at a selected site.
 7. The method according to any one of the previous claims further comprising determining in the three-dimensional image locations suspected of having a predetermined condition and indicating suspected locations in the displayed representation of the three-dimensional image.
 8. The method according to claim 7 wherein the predetermined condition is a malignancy.
 9. A system for selecting and recording biopsy sites in a body organ comprising: (a) A three-dimensional imaging device providing a three-dimensional image of a three dimensional region of the organ; (b) A two-dimensional imaging device providing two-dimensional sub-images of two-dimensional sub-regions of the three-dimensional region; (c) One or more display screens for displaying a representation of the three dimensional image and for displaying one or more two-dimensional images; (d) Means for selecting one or more sites in a two-dimensional sub-image where a biopsy is to be obtained; (e) A processor configured to: (i) determine the position of a two-dimensional sub-image in the three-dimensional image; (ii) display on a display screen a representation of a three-dimensional image with an indication of the position of a two-dimensional sub-image in the three-dimensional image; (iii) display on a display screen one or more two-dimensional sub-images; (iv) determine in a three-dimensional image any sites at which biopsies were obtained and indicate in a displayed representation of the three-dimensional image any sites at which biopsies were obtained;
 10. The system according to claim 9, further comprising a device for obtaining a biopsy at a selected site.
 11. The system according to claim 9 or 10 wherein the three-dimensional imaging device is a three-dimensional ultrasound imaging device.
 12. The system according to any one of claims 9 to 11 wherein the two-dimensional imaging device is a two-dimensional ultrasound imaging device.
 13. The system according to any one of claims 9 to 12 wherein representation of a three-dimensional image is a grid representation.
 14. The system according to any one of claims 9 to 13 wherein the processor is further configured to determine in a three-dimensional image locations suspected of having a predetermined condition and indicating suspected locations in a displayed representation of the three-dimensional image. 